The present invention relates to a safety net system that is placed upright on the ground as a rock fall restraining system to form a low impact barrier for restraining rock fall.
A number of barriers for restraining falling rocks are known. For example, in U.S. Pat. No. 4,819,915, Cargnel, a flexible barrier is disclosed that is provided with posts that pivot on a ground-anchored base plate, with the posts being held by wind bracing cables, some of which extend in an upstream direction and others of which extend in a downstream direction. An arresting net is secured to a series of spaced-apart horizontal ropes that are supported by the upstream wind bracing cable. U.S. Pat. No. 4,730,810, Rambaud, discloses a protective barrier that comprises a sheet of netting that is held upright by posts that in turn are held by upstream and downstream stays that are coupled to guide means that are further coupled to a mooring cable and to shock-absorbing means.
Such known protective barriers with retaining cables that extend transverse to the plane of the barrier are necessary for high impact situations. However, for lower impact barriers, it is not necessary to have such a complicated, expensive heavy duty system. Unfortunately, the heretofore known systems for low impact barriers, such as simple diagonal chain link and hexagonal mesh fencing, can withstand only very low impact forces and are subject to frequent maintenance.
It is therefore an object of the present invention to provide a barrier or safety net system for low impact situations that is extremely effective, requires little maintenance, and is also economical.